A 23-year-old man was walking along the public footpath from Oxenhope towards Deepdale Shops in Wildridings at around 7.20pm on Thursday 18 October, when he was approached by two men who told him they were police officers and needed to search him for drugs.
One man held the victim from behind while the other punched him in the face, before stealing his mobile phone.
About 15 minutes later, a 15-year-old boy was attacked by two men, believed to be the same offenders, in Bishopsdale.
The men told the victim they were police officers and ordered him to put his hands in the air while one offender held his neck. They took his mobile phone and when challenged, punched him in the face.
Investigating officer Det Con Luke Simms said: "We believe the offenders involved were responsible for a number of crimes that evening in the area of Wildridings.
"We would like to hear from anyone else who may have been approached that evening or witnessed two males acting suspiciously in that area between 7pm and 8pm."
A 28-year-old man from Bracknell was arrested in connection with the robberies. He was remanded in custody after being charged with unrelated offences in another force area.
A 24-year-old man, also from Bracknell, was arrested in connection with the robberies and released on bail until Thursday, November 8.
Contact Det Con Simms on 101 or Crimestoppers anonymously on 0800 555 111.